The present invention relates in general to interior-or exterior illumination means having a large light emitting surface extending around an axis, and in particular, to a device for eliminating glare of such illumination means.
In designing interior or exterior illuminating appliances effort is made to improve visual comfort and to achieve a high degree of illumination. For this purpose, lamps having a high light density must be free of glare. The elimination of glare is particularly needed in the case of large light emitting surfaces in matted incandescent lamps, mercury vapor high pressure lamps or fluorescent lamps, for example. Known non-glare measures employ an arrangement of simple screens, mirror systems and prismatic systems. The mirror systems and the prism systems, in general have the advantage that light, instead of being wasted by absorption, is deviated in the desired direction. Conventional prism systems, however, are disadvantageous for use in connection with a large light emitting surface which, for structural reasons, must lie very close to the prisms.
In this case, light rays cannot be prevented from impinging on the prisms from different angles and also from being dispersed in an uncontrollable manner, thus strongly imparing the desired effect.